This article is grounded in the premise that educators of out-of-school activities ought to build environments in which children can enjoy science and have positive experiences. The idea is backed by a broad consensus on learning science in early childhood. However, how can it be validated that a child really has had a positive experience in a given activity? What evidence would allow us to confirm that an educational proposal has truly been experienced in a positive way? The article addresses these questions through a specific case analysis of the activity 'Can I touch?', offered by the Natural Science Museum of Barcelona for children aged 2 to 6. The analysis identifies three areas to validate children benefiting from a particular experience in a positive way, and leads to the identification of operational factors relevant for the design and creation of new proposal
